Technology Review -- While the human heart was once thought incapable of regeneration, growing evidence shows that even the adult heart can grow new cells, albeit slowly. Roger Hajjar, director of the Cardiovascular Research Center at the Mount Sinai School of Medicine, in New York, and Bernhard Kuhn, a cardiologist at Children's Hospital Boston, aim to harness this regenerative ability to change how heart disease is treated. They cofounded a startup called CardioHeal, based in Brookline, MA, to develop peptide drugs that can spur growth of new heart muscle cells in the human body.